Electrical apparatus



- I. H. SC LATER. ELECTRICAL APPARATUS.- APPLICATION FlLED DEC.24. I917- Patented Sept. 9, 1919.

Fig.1.

litrwventmr": mhae. Z"? S ciat A;

H 5 M'Ett car-n61: g

-V,UN ITED sTA'rps PATENT OFFICE.

IVANHOE H. SGLATER, OF PITTSFIE-L-D, MASSACHUSETTS, ASSIGNOR TO GENERAL ELECTRIC COMPANY,JA CORPORATION OF NEW YORK.

ELECTRICAL APPARATUS.

' 1 Patented Sept. 9, 1919.

Application filed December 24, 1917. Serial No. 208,575.

Pittsfield, in the county of Berkshire, State of Massachusetts, have invented certain new and useful Improvements in Electrical Apparatus, of whichthe following is a spec1fication.

be understood therefrom.

My invention relates to electrical induction apparatus, such for example as transformers, autotransformers, some reactances, etc; my invention relates particularly, however, to reactances provided with cores ofmagnetic material.

One object of my invention is to improve the construction and operating characteristics of those devices of the class indicated, the cores of which have air gaps" or interruptions in the magnetic circuit; another object is to provide such devices with more suitable gaps or interruptions in the magnetic circuit thereof. Other objects will appear from the matter hereinafter. For simplicity and because my invention relates particularly to such devices,

I shall hereafter mostly de cribe my inven-' tion with reference to react-ances; its app lication to other induction apparatus vwill Itis desirable to provide the cores of magnetic material of some reactances with air gaps, or interruptions in the magnetic circuit transverse to the lines ofv magnetic fiuX, 'in order to prevent or limit the magnetic saturation of the cores and in tha't way allow the use of smaller cores. Generally these gaps are preferably located in the parts of the cores inclosed by. the windings. When considerableinterruption of the magnetic circuit is necessary, a plurality of small gaps are preferable to a single large gap, for a large gap causes undue fringing of magnetic flux about the gap and undue leakage 'of the fluX.- In fringing, a part of the flux crosses the gap curves outwardly from the core into the space for the windings, thereby increasing the eddy currents and heating; by leakage is meant that part of f the flux completes its pathoutside the path across the magnetic circuit, and bridgedgaps which er itend only partly across the windings.

magnetic circuit,but not both types in the same core. Where one small gap in each leg of the core is sufficient, as in small reactances forexample, it has been customary to use complete gaps. Complete gaps areunsatisfactory, however, for reactances where a number of gaps are required in each core leg, for a number of complete gaps in in any. one core leg results in detachmg one or more parts of the core from the remainder and there is no satisfactory simple way known forholding such detached parts in place when the core gaps are within the Consequently bridged gaps, extending only partly across the core, have been used wherevera number of gaps per core leg. are required within the winding, for such gaps eliminate the devices for holding the (otherwise) detached core parts in place. While bridged gaps are thus satisfactory from a mechanical point of view, such bridged gaps have been found to introduce higher harmonics into the electric circuits and higher harmonics are undesiris possible V the device and the operating characteristics I thereof. Accordingly my invention consists, briefly, in providing each core leg with a single complete gap and in addition-as many more bridged gaps as may be necessary to secure the desired interruption of the magnetic'circuit. In such a reactance there are no detached core parts, and hence no devices particularly for supporting such detached parts, and the harmonics introduced into the electric circuits may be reduced to a. low value without introducing prohibitive fringing of the flux at the complete gaps. In the accompanying drawing and the following description I haveillustrated and. described vin some detail the best embodi ment of my invention of which I am now aware. Figure 1 diagrammatically represents in elevation a reactaiiceembodyipg my invention, the windings being broken away in part to show the core legs. Fig. 2 is a sectio all View of one of the core legs looking in the direction of the arrows 2 -2 through the flanges of Fig. 1. Figs. 3 and at show parts of the narrow and the wide laminations of the core at bothsides of the complete gaps.

The reactance of Fig. l in general is very similar to those heretofore known. It consists essentially ofa core 10, generally reotangular in outline and providing the windin legs 11 and 12. The core is laminated in the well-known manner and each windin leg is cruciform in cross-section. Combined core clamps and coil supports 15, each comprising in general an L-shaped member, are disposed as usualat-the sides of each yoke of the core and are tightly'clamped to the yokes by the bolts 16. A bolt 17 at each side of the reactance extends substantially parallel to the winding legs and passes of the clamping members 15 st the same side of the core. These bolts 17 clamp the top of the reactance to the bottom and'ren'der the whole device a strong unitary structure iii spite of the gaps extending completely across the magnetic circuit as hereinafter described in detail. The windings 18 and 19 surround the winding 11 nd 12 respectively and are supported by and between the flanges of the clamps 15 as illustrated.

Each winding. leg is provided with one complete gap 22, extending completely across and completely interrupting the same, and witha plurality of bridged gaps ex tending only partly across each lamination. Figs. 3 and -lperhaps better illustrate the gaps. 'l ig. 3 illustrates one of the narrow layers or laminations of one of the winding legs, that is, one of the laminations occupying on of the parts of the core leg (see Fig. Fig. a shows one of the wide laminations or one of the laminations occupying the part 26 of the core leg. As will be seen from Figs. 3 and 4, each lamination of magnetic material is provided with a gap 22 extending completely across it; the path of the flux through this lamination is completely interrupted at 22. Each'lamination is like wise provided with bridged gaps 23, a. small width of the magnetic materialbeing left opposite each of the gaps 23 at the em treme edges of the lam-inations. The gaps in the different lan'iinations are so disposed that all the gaps 22 of all the laminations in any one core log are arranged opposite each other; and likewise each gap 23 in any one lamination is arranged opposite a similar gap in the lamlnations adjacent it. Thus the core legs, as well as each lamination thereof, is completely interrupted at 22, and the bridged gaps in the diii'erent laminations result in holes completely through the core leg. illustrated in Fig. l. The complete gap 22 in each core leg is tilled with some strong non-magnetic material; then as the nuts at the ends of the bolts 17 are screwed down the ends of the lamination at the gaps tightly compress the filling material and the whole reactance has great mechanical strength. The gaps 23 may also be filled with nonmagnetic material if desired. For mechanical strength the non-magnetic filling material of each'of the gaps 22 and 23 is preferably applied as a single block or in the form of a number of layers extending transversely to the axis of the winding YVhileI have described the principle of my invention and the best mode I have contemplated for applying this principle, other modifications will occur to those skilled in this art and I aim in the appended claims to cover all modifications which do not involve a departure from the spirit and scope of my 7 invention.

\Vhat I claim as new and desire to Secure by Letters Patent of the United States, is 1. Electrical apparatus comprising a core oi magnetic material provided with gaps,

and windings surrounding said core. said gaps including a gap extending completely .across the magnetic circuit and a bridged This arrangementof the gaps is and windings on said core, said gaps being located in a portion of the core surrounded by said windings and including a gap extending completely across the magnetic circuit and a bridged "gap eXtending partially across said magnetic circuit.

3. A core of magnetic material and windings thereon forming a reactance, said core being provided with gaps within said windings, said gaps including a. gap extending completely across the magnetic circuit and a plurality of bridged gans each extending partially across the magnetic circuit.

in witness whereof. I have hereunto set my hand this 21st day of December 1917.

TVANHO Tr) ll. "3 (1i nrTE t. 

